Daring Fireball‘s John Gruber may be the web’s most influntial Apple blogger, but before he took up full-time punditry, he was a designer and techie. So the news that he’s co-created an iPhone app with Brent Simmons and Dave Wiskus, while unexpected, makes more sense the more you think about it. Gruber is a man of strong opinions about iPhone app design; now he’s expressed them in the form of an app rather than a blog post.

The app in question is a note-taking program, called — in a Gruber-esque James Bond reference — Vesper. And if you read Daring Fireball you can pretty much guess its broad brushstrokes. You’d figure that it would emphasize simplicity over sheer number of features and that the interface would exude polished minimalism. What’d you’d expect, especially if you remember what Gruber has written about other note-taking apps, would be a sort of anti-Evernote. And you’d be right.

Vesper lets you enter notes, tag them and add photos. You can filter notes down to ones bearing a particular tag, shuffle their order by sliding them about and archive them by swiping them off the screen. And that’s about it.

The app looks gorgeous, with distinctive typography and a notable absence of textures, lines and other fripperies that would clutter up the interface without adding value. And the gestures you use to get around are all intuitive and efficient.

Even if you admire the way Vesper sets out to do only a few things but do them well, the odds are reasonably high that you’ll wish it had a feature or two that it lacks — if nothing else, some way to get notes off your iPhone and onto other devices. It seems like a given, however, that any future versions won’t pile on new features willy-nilly. For Vesper, less is presumably going to continue to be more.

There’s nothing radically new about this software, but by doing what it sets out to do so well, it proves that even an absurdly crowded App Store category such as note takers always has room for one more worthy contender. If you bristle at the fact that it costs $4.99 — a tad pricey for an iPhone note taker — it’s likely not the sort of app that would appeal to you, and you’ll be fine with one of the umpteen free options out there.